While Gary maybe was the first person to use "insegrevous" on television, he didn't create the word but overheard it being used by Chuck Ferguson who was using the word in his "Simon Says" audience warm-up routine for Golden West Broadcasting.
In truth, the word came about during a 1986 creative writing assignment at Moorpark College. The English professor was Michael Strumpf and his class assignment was to "... come up with a catch-all word that can be used for virtually any part of speech and mean virtually anything you want it to mean."
Chuck still continues to use this word even today and has been known to use it in a variety of situations including law school examinations, in business proposals, loan and employment applications, job resume', business lectures and seminars, even when testifying in Court!?
The definition of the word is most affected by the manner in which it's communicated, e.g., other words to which it's affiliated, tone and voice inflection, coupled with facial expression and gestures.
Noteworthy is that in the last four decades, Chuck's use of the word has been challenged only once! The girls name was Tammy and she was 11 years old.
The cops have reason to believe that the suspect is a known insegreviate.
While the idea was insegreviously accepted by most, there remained a few who still needed to be persuaded.
Your Honor, it was just one of those insegrevious situations for which I have no excuse!
Insegreviology: The study of anything ... or nothing at all!
The other story about Chuck Ferguson and "Simon Says" is clearly wrong, as Laugh-In started in 1968 and "insegrevious" and the Funk & Wagnalls listing had already happened then. The "Simon Says" pilot didn't happen until 1971.